An Unseen World Beneath Our Feet - Caves, Sinkholes and Springs

Beneath a quarter of the United States are rock types that can dissolve to form caves, sinkholes and other features. Nearly every state in the nation has rock layers beneath our feet of limestone, gypsum, and other soluble rocks we call "karst". Karst is important for many reasons. Almost half of the ground water used for drinking comes from karst aquifers, and karst regions such as the Shenandoah Valley of Virginia are some of the most productive agricultural lands in the nation. However, the rock layers underneath karst dissolve easily, sometimes creating sinkholes that can be a threat to life and property. Yet these soluble rock layers also yield some of the most beautiful and unique natural environments found in many of our national and state parks.Follow this event live on Twitter @USGSLiveTo request accommodations, please call or email jcorley@usgs.gov or 703-648-7770